1. Field of the Invention
The present invention relates to an optical apparatus for an all-optical processing for an optical input such as an optical image, an optical signal or the like and, more particularly, to an optical apparatus suitably used for an ultrafast optical waveshaping, an ultrafast optical gate processing and the like.
2. Related Background Art
There is no conventional apparatus for an all-optical processing, e.g., an optical gate processing by controlling an optical path of input light. For example, as a prior art for optically waveshaping an optical input on the order of subnanoseconds, a technique described in the reference entitled "Generation of Arbitrarily Shaped Optical Pulses in the Subnanosecond to Picosecond Region Using a Fast Electrooptic Deflector" (IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. QE-16, NO. 2, FEBRUARY 1980) is known. This optical waveshaping apparatus employs an electrooptic deflector (EOD) and a slit. An applied voltage to the EOD is changed in an AC manner while an input beam is incident on the EOD, and a deflected transmission beam is radiated on the slit, thereby obtaining a waveshaped output pulse from the light transmitted through an opening of the slit. Since this apparatus employs the EOD, an electrical signal must be used in deflection of an input beam, and various problems are inevitably posed in association with the electrical signal.
As a framing camera used in subnanosecond image framing, techniques described in Japanese Patent Laid-Open No. 64-60944 and in the reference entitled "Single-Frame and Double-Frame operation of a Picosecond framing camera" (Vol. 57, No. 6, Apr. 15, 1986) are known. In a gate apparatus in the conventional framing camera, spatial image information is converted into an electron beam by a photo cathode, and the electron beam is scanned by the deflector to pass through a slit. When the image information passes through the slit, it is converted into time-serial information. After the image information passes through the slit, the information is deflected again, and becomes spatial image information when it forms a fluorescent image on an output surface. In this apparatus, image information as light is temporarily converted into electron information, and the converted information is subjected to processing. Therefore, the photo cathode and the phosphor screen are indispensable, and sensitivity is inevitably decreased, thus causing various drawbacks. Since an electron tube which causes a decrease in resolution due to a space-charge effect is used, the apparatus is easily damaged. A high voltage must be applied, and a circuit is undesirably complicated.